Improve: Move more logic to ViewModel

src/main/kotlin/com/looker/droidify/ui/appsList/AppListFragment.kt

@@ -2,7 +2,6 @@ package com.looker.droidify.ui.appsList
 
 import android.database.Cursor
 import android.os.Bundle
-import android.os.Parcelable
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -22,7 +21,7 @@ import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
 import io.reactivex.rxjava3.core.Observable
 import io.reactivex.rxjava3.disposables.Disposable
 import io.reactivex.rxjava3.schedulers.Schedulers
-import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.first
 
 class AppListFragment() : BaseFragment(), CursorOwner.Callback {
 
@@ -30,7 +29,6 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
 
     companion object {
         private const val EXTRA_SOURCE = "source"
-        private const val STATE_LAYOUT_MANAGER = "layoutManager"
     }
 
     enum class Source(val titleResId: Int, val sections: Boolean, val order: Boolean) {
@@ -48,51 +46,10 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
     val source: Source
         get() = requireArguments().getString(EXTRA_SOURCE)!!.let(Source::valueOf)
 
-    private val searchQuery: String
-        get() {
-            var _searchQuery = ""
-            lifecycleScope.launchWhenCreated { viewModel.searchQuery.collect { _searchQuery = it } }
-            return _searchQuery
-        }
-    private val section: ProductItem.Section
-        get() {
-            var _section: ProductItem.Section = ProductItem.Section.All
-            lifecycleScope.launchWhenCreated { viewModel.sections.collect { _section = it } }
-            return _section
-        }
-    private val order: ProductItem.Order
-        get() {
-            var _order: ProductItem.Order = ProductItem.Order.LAST_UPDATE
-            lifecycleScope.launchWhenCreated { viewModel.order.collect { _order = it } }
-            return _order
-        }
-
-    private var layoutManagerState: Parcelable? = null
-
     private var recyclerView: RecyclerView? = null
 
     private var repositoriesDisposable: Disposable? = null
 
-    private val request: CursorOwner.Request
-        get() {
-            val searchQuery = searchQuery
-            val section = if (source.sections) section else ProductItem.Section.All
-            val order = if (source.order) order else ProductItem.Order.NAME
-            return when (source) {
-                Source.AVAILABLE -> CursorOwner.Request.ProductsAvailable(
-                    searchQuery,
-                    section,
-                    order
-                )
-                Source.INSTALLED -> CursorOwner.Request.ProductsInstalled(
-                    searchQuery,
-                    section,
-                    order
-                )
-                Source.UPDATES -> CursorOwner.Request.ProductsUpdates(searchQuery, section, order)
-            }
-        }
-
     override fun onCreateView(
         inflater: LayoutInflater,
         container: ViewGroup?,
@@ -114,14 +71,13 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
-        layoutManagerState = savedInstanceState?.getParcelable(STATE_LAYOUT_MANAGER)
 
-        screenActivity.cursorOwner.attach(this, request)
+        screenActivity.cursorOwner.attach(this, viewModel.request(source))
         repositoriesDisposable = Observable.just(Unit)
             .concatWith(Database.observable(Database.Subject.Repositories))
             .observeOn(Schedulers.io())
             .flatMapSingle { RxUtils.querySingle { Database.RepositoryAdapter.getAll(it) } }
-            .map { it.asSequence().map { Pair(it.id, it) }.toMap() }
+            .map { list -> list.asSequence().map { Pair(it.id, it) }.toMap() }
             .observeOn(AndroidSchedulers.mainThread())
             .subscribe { (recyclerView?.adapter as? ProductsAdapter)?.repositories = it }
     }
@@ -136,18 +92,14 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
         repositoriesDisposable = null
     }
 
-    override fun onSaveInstanceState(outState: Bundle) {
-        super.onSaveInstanceState(outState)
-        (layoutManagerState ?: recyclerView?.layoutManager?.onSaveInstanceState())
-            ?.let { outState.putParcelable(STATE_LAYOUT_MANAGER, it) }
-    }
-
     override fun onCursorData(request: CursorOwner.Request, cursor: Cursor?) {
         (recyclerView?.adapter as? ProductsAdapter)?.apply {
             this.cursor = cursor
+            viewLifecycleOwner.lifecycleScope.launchWhenCreated {
                 emptyText = when {
                     cursor == null -> ""
-                searchQuery.isNotEmpty() -> getString(R.string.no_matching_applications_found)
+                    viewModel.searchQuery.first()
+                        .isNotEmpty() -> getString(R.string.no_matching_applications_found)
                     else -> when (source) {
                         Source.AVAILABLE -> getString(R.string.no_applications_available)
                         Source.INSTALLED -> getString(R.string.no_applications_installed)
@@ -155,16 +107,13 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
                     }
                 }
             }
-        layoutManagerState?.let {
-            layoutManagerState = null
-            recyclerView?.layoutManager?.onRestoreInstanceState(it)
         }
     }
 
     internal fun setSearchQuery(searchQuery: String) {
         viewModel.setSearchQuery(searchQuery) {
             if (view != null) {
-                screenActivity.cursorOwner.attach(this, request)
+                screenActivity.cursorOwner.attach(this, viewModel.request(source))
             }
         }
     }
@@ -172,7 +121,7 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
     internal fun setSection(section: ProductItem.Section) {
         viewModel.setSection(section) {
             if (view != null) {
-                screenActivity.cursorOwner.attach(this, request)
+                screenActivity.cursorOwner.attach(this, viewModel.request(source))
             }
         }
     }
@@ -180,7 +129,7 @@ class AppListFragment() : BaseFragment(), CursorOwner.Callback {
     internal fun setOrder(order: ProductItem.Order) {
         viewModel.setOrder(order) {
             if (view != null) {
-                screenActivity.cursorOwner.attach(this, request)
+                screenActivity.cursorOwner.attach(this, viewModel.request(source))
             }
         }
     }

src/main/kotlin/com/looker/droidify/ui/appsList/AppListViewModel.kt

@@ -2,12 +2,10 @@ package com.looker.droidify.ui.appsList
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.looker.droidify.database.CursorOwner
 import com.looker.droidify.entity.ProductItem
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.*
-import kotlinx.coroutines.flow.SharingStarted
-import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 
 class AppListViewModel : ViewModel() {
@@ -21,6 +19,7 @@ class AppListViewModel : ViewModel() {
         scope = viewModelScope,
         started = SharingStarted.WhileSubscribed(5000)
     )
+
     val sections: StateFlow<ProductItem.Section> = _sections.stateIn(
         initialValue = ProductItem.Section.All,
         scope = viewModelScope,
@@ -32,6 +31,32 @@ class AppListViewModel : ViewModel() {
         started = SharingStarted.WhileSubscribed(5000)
     )
 
+    fun request(source: AppListFragment.Source): CursorOwner.Request {
+        var mSearchQuery = ""
+        var mSections: ProductItem.Section = ProductItem.Section.All
+        var mOrder: ProductItem.Order = ProductItem.Order.NAME
+        viewModelScope.launch { searchQuery.collect { if (source.sections) mSearchQuery = it } }
+        viewModelScope.launch { sections.collect { if (source.sections) mSections = it } }
+        viewModelScope.launch { order.collect { if (source.order) mOrder = it } }
+        return when (source) {
+            AppListFragment.Source.AVAILABLE -> CursorOwner.Request.ProductsAvailable(
+                mSearchQuery,
+                mSections,
+                mOrder
+            )
+            AppListFragment.Source.INSTALLED -> CursorOwner.Request.ProductsInstalled(
+                mSearchQuery,
+                mSections,
+                mOrder
+            )
+            AppListFragment.Source.UPDATES -> CursorOwner.Request.ProductsUpdates(
+                mSearchQuery,
+                mSections,
+                mOrder
+            )
+        }
+    }
+
     fun setSection(newSection: ProductItem.Section, perform: () -> Unit) {
         viewModelScope.launch(Dispatchers.Main) {
             if (newSection != sections.value) {